Hiram s



(No Model.)

' H. S. MAXIM.

Process of Manufacturing Carbon Conductors.. No. 230,309. Patented july 20, H88@ Nrrnn Warrent- HIRAM s. MAXIM, OF BROOKLYN, Assiettes TO SPENCER D. sonovnnn, on

' NEW YORK, n. Y.

PROCESS oF MANUFACTURING cannon continuerons.

SPECIFICATION forming part of Letters Patent No. 230,309, dated Ju1y 20, 188i).

Application filed 'March 22, 1890. (Nomodel.)

To all whom tt may concern:

Be it known that I, HIRAM S. MAXIM, ofthe city of Brooklyn, county of Kings, and State of N ew York, have invented a certain new and useful Process of Manufacturing Carbon Gondoctors for Electric Lamps, of which the following is a. specilication, reference being had to the accompanying drawings, whichnfornl a part hereof.

My invention relates more particularly to making carbon conductors for electric llamps producing light by the incandescence of acon- Iinuous strip or conductor; but it may be ap plied to manufacturing carbon for other uses where comparatively small strips or pieces of dense and tough carbon are desired,

j A 4-variety' of different carbonaceous substancesmay be carbonized by my improved process, such as wood, the inner bark of trees, card-board, paper and silk, cotton, or linen fabrics. The material used is cnt or bentinto pieces of the shape desired for the conductor ofthe lamp, but somewhat larger in each dimansion to allow for shrinkage,` and is then charred in a suitable retort while a current of` hydrocarbon lvapor or` gas is flowing through the retortand enveloping the material.

I have shown in the drawingsan apparatus suitable for making carbon conductors accord' ing to this process; but I do not wish to be confined to the particular apparatus shown, as the process may be performed with equal facility with other forms of apparatus.

In the drawings, Figure lis a longitudinal vertical section ot' the apparatus. Fig. 2 is a plan or top view, and Fig. 3 shows a form of vthe carbonizer, and b is a gas-supply pipe.

C is a sheet of metal placed in the carbonizer, end supported a short distance above the bottom vof it by short posts c c.

A sheet of tissueLpaper is placed upon the plate C, and 'a layer of the forms of material is stove and heated toa temperature sutticientlyhigh to expel the aqueous vapor contained in the pores of the material, but not snfciently high to char the material to any considerable extent, Vand the carhureted gas is admitted to Ythe carbonizer through the pipe a and ignited where it escapes through the sand atv the top. After the material'has been subjected to this heating for a 'considerable time-say ten or twelve hours-fthe carbonizer is placed in a inutile-furnace and raised to a white heat and kept there until all the material is thoroughly charred, the gas being all the time supplied to the carbonizer through the pipe a and circulating about the forms, so as to envelop them on all sides. Ordinary coal-gas may be used for this purpose; but, unless it is rich in carbon, it should be carbureted with gasoline or i some other volatile hydrocarbon oil, and I prefer tocarburet it in all cases. A convenient -form of carbureter to be used for this purpose is shown at B in the drawings, where b is a' pipe supplying coal-gas and opening below the surface of the oil,andais thedelivery-pipe for the carbnreted gas. The function oi the gas during the irstpart of theprocess, as nearlyas I can at present ascertain, is to permeate the pores of the material and drive out the aque ous vapor and air contained, in them as-far as possible, and its function during the latter or charring part ot the process seems to be to protect and consolidate the carbon of the inaterial. When the hydrogen and other constituents are disassociated from the carbon of the material by the heat of the furnace the surrounding hydrocarbon vapor or gas is also probably decor'npose'd, and some. part of the gasor vapor. In this way nearly if notquite all sawdust, so as to preventall access of air to the forms while they arehot.

carbon thus liberated, especially that which` .keeping up the supply of gas.

yWay.

is contained in the pores of the material, is ap# parently deposited upon the carbon of the forms,- and serves to consolidate it. The -hydrogen, when liberated, doesnot corrode the carbon of the forms, but, i t' it has any tendency to again. take up carbon, probably unites with some partof the free carbonliberated from the ofthe carbon of the carbonized material ispreserved, and, as carbon liberated from a gas or vapor-at high temperatures has a tendency to deposit upon any solid carbon present, the. carhous ofthe forms may apparently be built up to a considerable extent by maintaining the white heat for a sufficiently long -period and I prefer,how ev r, to remove the carbonizer from the fu'rnace soon after the forms have become .thoroughly carbonized and before any considerable amount of carbon from the gas has been deposited upon them'. I find thattwoor three hours is usually suihcient for this purpose, and the carbonizer is then removed 'from the furnace and allowed to cool. The current "of gas is kept passing through the c arboniyzei` iintil it is so far cooled `that it will notigm'tedry I ind that-carbon made bythis process. is more dense and tough than any which I have seen made by otherprocesses, 'and the forms shrink less than when carhonized in`the`nsual The essential feature ot the process is the enveloping of the forms vin an. atmosphere or current ot' hydrocarbon gas or vapor during the carbouizing, and the preliminary heating and the subsequent passage of the gas through th carbonizer are not essential, although I find that better results are secured by so conducting the process.

l I am awa-re that such carbon conductors have heretofore been made by carbonizing wood, paper, pith of trees, and other carbonaceous vegetable substances at a high temperature, and I- do not claim carbonizing such materials independen t-ly of the process described;

but,

Havingdescribed myinvention,what I claim4 as new, and desire to secure by Letters Patent,

1. The processv of carbonizing carbonaceous -substances by exposing them to a high telnperature while surrounded by'hydrocarbon gas or vapor, substantially as described.

2. The process of making carbon conductors- HIRAM s. MAXIM.y

Witnesses MELVI'N BROWN, LEONARD E. CURTIS. 

